1. Field of the Invention
The present invention relates to a recording material for an image forming apparatus such as a copying machine, a printer or the like, particularly an image forming apparatus having a fixing roller which is coated with a releasing agent.
2. Description of the Related Art
Fixing devices widely used for image forming apparatuses include devices of a roller fixing type, particularly a heat roller fixing type, in which a toner image on a recording material is fixed by conveying the recording material between two rollers.
Typical recording materials include paper. However, resin films such as transparency films and the like are increasingly being used as recording materials.
Further, a heated roller type of fixing device is coated with a releasing agent such as silicone oil or the like in order to prevent offset of the toner used.
In a full-color image forming apparatus in which toner is applied in layers, a large amount of silicone oil is coated on a fixing device because the toner easily offsets.
When a toner image on a resin film is fixed by such a fixing roller which is coated with silicone oil, there is the problem that the oil wets the resin film which then has a sticky feeling after fixing.
The sticky feeling is caused by oil which is not absorbed by the resin film and thus remains on the film surface. However, when a recording material is made of paper, the paper material does not have the above sticky feeling because the coated oil is absorbed by the paper due to the oil absorptivity of paper.
In addition, when a full-color image is formed on such a resin film and is used as a projected image by an OHP apparatus, the projected image contains components showing an overall gray tone in spite of the satisfactory color development shown by the image on the film, and the range of color reproduction is significantly narrowed. This is caused by the phenomenon that since the toner formed on the smooth transparent film is caused to insufficiently flow to form grains by heating during fixing, the incident light is scattered and thus forms shadow on a screen during projection of the image. Particularly, in a portion having a low image density and an intermediate tone, since a decrease in number of toner grains causes the absorption level of the dye or pigment contained in the toner to be decreased to the same level as that of black absorption caused by the light scattered by the toner grains, a color tone to be reproduced is grayed.
In addition, when an image is formed on paper, since a difference occurs between the non-glossiness of the paper surface and the glossiness of the portion where the toner image is formed, uniform glossiness within the paper, which is desirable for a color image, disappears. This causes the problem that a desirable image having good colors is not formed.